Paper break detector



April 1937- P. JUCHTER 2,078,800

PAPER BREAK DETECTOR Filed Dec. 3,- 1936 Fig.3.

nuunuu 3 I C I Inventor:

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Patented Apr. 27, 1937 UNITED STATE PAPER BREAK DETECTOR Pieter Juchter, Scotia, N. Y., minor to General Electric Company, a corporation 01' New York Application December 3,1936, Serial No. 114,006

3 Claims.

My invention relates to apparatus employing photoelectric means for detecting a break in a paper strip such for example as the paper which is being printed in a modem rotary web press. Previous to my invention attempts which have been made to use such means for the detection of a break in a paper strip during the printing operation have been unsuccessful due to an accumulation of ink on the photoelectric device and on the lamps employed in sufflcient quantity to cause the apparatus to indicate a break when no break has occurred. It is the object of my invention to provide improved apparatus of this character with which the difliculty previously 15 encountered may be overcome.

In accordance with my invention I protect the photoelectric device and preferably the light source also from the material which may collect thereon by means of an enclosing casing having a 20 window which is so arranged with reference to the paper strip that the latter wipes across it and keeps it clean.

My invention will be better understood from the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

Referring to the drawing, Fig. l is a crosssectional view illustrating one embodiment of my invention; Fig. 2 is a side view of the same with parts shown in section; and Fig. 3 illustrates a drive for the paper strip together with a circuit diagram of the control apparatus.

In Fig. 1 the paper strip is shown at l, a break in which is to be indicated by the apparatus comprising my invention. Two light sources are shown at 2 and 3 which, for example, may be incandescent lamps which serve to illuminate a portion of the strip I. Light reflected from this illuminated portion is received by the photoelec- 40 tric device 4, such for example as a photoelectric tube, and as long as this device is receiving a predetermined amount of light the apparatus for driving the strip remains operative.

It is well known that in the vicinity of modern printing presses, such for example as presses employed in the printing of newspapers, the atmosphere in the vicinity of the press is laden with ink vapor. In apparatus of this character as heretofore employed this vapor has soon 50 covered the photoelectric device as well as the lamp source with an opaque coating which rendered the apparatus inoperative. To protect the photoelectric device 4 and the lamps 2 and 3 from deposits of ink vapor I have provided the 55 enclosing casing 5 which is shown as comprising the base portion 6 to which the cover I is detachably secured as by the wing nuts .8. The entire casing may be adjustably mounted on a fixed member represented at 9 by means of the ears In on the base which may be clamped to the support by the bolt ii. The base portion 6 also serves to support the photo device 4 and the lamps 2 and 3. The cover 1 preferably is provided with the two partitions I2 which separate the two lamps from the photoelectric device to prevent the device from receiving light directly from the lamps. At its lower side the casing is provided with a window which comprises the opening l4 and the cover glass i5 which makes a tight joint with the wall of the casing and is shown held in place by the locking ring I6. Light from each of the lamps 2 and 3 is free to pass down through the window on to the paper strip where it is reflected back through the window into the photoelectric device 4..

An important feature of my invention is that the casing containing the light sources and photoelectric device is arranged so close to the paper strip that the latter rubs across the outer surface of the glass of the. window and keeps it clean. It is well known that where the paper strip is travelling at a relatively high speed it is set into transverse vibration. In Fig. 1 the casing is shown tilted slightly in order that the crests of the vibration waves set up in the paper will wipe more or less evenly over the entire face of the glass and thus remove any ink therefrom as fast as it may collect. The casing 5 may be arranged opposite any point in the width of the paper strip but when the strip has printing thereon I preferably arrange the casing so that the window comes opposite a marginal portion which is without printing.

In Fig. 3, I have represented by way of example only a drive for the paper strip. This drive is shown as comprising two pinch rolls [8 and IS, the latter of which is shown driven by the motor 20 through the worm gearing 2|. The motor 20 is shown connected through the relay 22 with the source of current 23, which source also supplies the lamps 2 and 3. The photoelectric device 4 connects through the amplifier 24 with the winding of the relay 22, the circuit arrangement of the photo device and the amplifier being shown, for example, like that disclosed in the Cockrell et a1. Patent 1,964,454-June 26, 1934.

With this apparatus the paper strip normally reflects light from the lamps into the photoelectric device which, as a result, maintains the relay 22 in the closed circuit position to keep the driving motor energised. 11', however, a break should -cccurin thestri'pbetween the pinchrollsandthe casing containing the photoelectric device the res suiting decrease in the reflected light received by I the photo device allows the relay 2! to open the motor circuit and thus stop the drive. By causing the moving strip to wipe across the window oi the casing containing the photo device and the 10 light source the window is automatically kept clean regardless o! the amount of ink vapor that may be present in the surrounding atmosphere.

Since normally the photoelectric device is receiving light from the lamps reflected by the 16 paper strip, the amplifier is passing current and the relay is energised, should any 01' those parts become inoperative due, for example, to a burning out oi the lamps, to a broken photo or amplifier tube or to an open or short circuited relay wind- 80 ing, the strip drive stops. It will not operate again until the break detector apparatus is suitably repaired and again put in reliable functioning condition. I

I have chosen the particular embodiment de- 86 scribed above as illustrative oi my invention and it will be apparent that various modifications may be made without departing from the spirit and scope of my invention which modifications I aim to cover by the appended claims.

whatliclaimasnewanddeslretosecureby Letters Patent of the United States is: I

1. In combination, means for moving a paper strip, a photoelectric device arranged to receive light controlled by said strip. means responsive to said device for controlling said moving means and an enclosing casing for said device having a window arranged to be rubbed by said strip.

2. In combination, means for moving a paper strip, a light source, a photoelectric device arranged to receive light from said source reflected by said strip, means responsive to said device for controlling said moving means, a casing enclosing said source and device and provided with a window, said window being arranged to be rubbed by said strip.

3. In combination, means for moving a paper strip, a plurality of light sources, a photoelectric device, means responsive to said device for controlling said moving means, a casing enclosing said sources and device and having partitions separating the sources from the device, said casing having an opening and a glass closure therefor through which light from said sources may pass to said strip and through which the light reflected by the strip may be received by the device, said closure being arranged so close to said strip that it is wiped and kept clean thereby.

PIETER JUCHTER, 

